title: Development and characterization of a novel mAb against bilitranslocase - a new biomarker of renal carcinoma.
abstract: BACKGROUND
  Bilitranslocase (TC 2.A.65.1.1) is a bilirubin-specific membrane transporter, found on absorptive (stomach and intestine) and excretory (kidney and liver) epithelia and in vascular endothelium. Polyclonal antibodies have been raised in rabbits in the past, using a synthetic peptide corresponding to AA65-77 of rat liver bilitranslocase, as an antigen. Affinity-purified antibodies from immune sera have been found to inhibit various membrane transport functions, including the bilirubin uptake into human hepatocytes and the uptake of some flavonoids into human vascular endothelial cells. It was described by means of immunohistochemistry using polyclonal antibodies that bilitranslocase expression is severely down-regulated in clear cell renal carcinoma. The aim of our work was development and characterization of high-affinity, specific mAbs against bilitranslocase, which can be used as a potential diagnostic tool in renal cell carcinoma as well as in a wide variety of biological assays on different human tissues.
  
  
  METHODS
  Mice were immunized with a multi-antigen peptide corresponding to segment 65-75 of predicted primary structure of the bilitranslocase protein. By a sequence of cloning, immune- and functional tests, we aimed at obtaining a specific monoclonal antibody which recognizes a 37 kDa membrane protein, and influences the transport activity of bilitranslocase.
  
  
  RESULTS
  On the basis of previous results, specific IgM monoclonal antibodies were produced in BALB/c mice, in order to further improve and extend the immunological approach to the study of bilitranslocase in renal cancer cells as well as to develop its potential diagnostics use.
  
  
  CONCLUSIONS
  In this article we show an immunological approach, based on newly developed monoclonal antibodies, to a detailed biochemical and functional characterization of a protein whose gene and protein structure is still unknown. We were able to demonstrate our novel mAb as a tumor marker candidate of renal cell carcinoma, which may prove useful in the diagnostic procedures.
authors.affiliation: Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia.
authors.forename: Sendi
authors.initials: S
authors.lastname: Montanic
authors.forename: Michela
authors.initials: M
authors.lastname: Terdoslavich
authors.forename: Uros
authors.initials: U
authors.lastname: Rajcevic
authors.forename: Luigina
authors.initials: L
authors.lastname: De Leo
authors.forename: Serena
authors.initials: S
authors.lastname: Bonin
authors.forename: Vladka Curin
authors.initials: VC
authors.lastname: Serbec
authors.forename: Sabina
authors.initials: S
authors.lastname: Passamonti
keywords: bilitranslocase; kidney; monoclonal antibody; peptide antigen; renal cell carcinoma; tumor marker